Deflection system for triad-beam cathode ray tube

ABSTRACT

A cathode ray tube deflection system includes a triad-type cathode ray tube and a toroid-type deflection yoke having horizontal and vertical axes with first and second horizontal windings symmetrical to the horizontal axis in mirror image of one another about the vertical axis and first and second vertical winding symmetrical to the vertical axis in mirror image of one another about the horizontal axis and said first and second horizontal and vertical windings each including a flux altering means for enhancing vertical convergence of horizontal trace lines. The deflection yoke is formed by a process wherein a core of magnetic material is wrapped with wire turns applied in toroidal fashion to form first and second horizontal windings and first and second vertical windings advanced in opposite circumferential direction to form a mirror image relationship. Also, &#39;&#39;&#39;&#39;ringing&#39;&#39;&#39;&#39; is inhibited by circuitry wherein a specific terminal of each of the horizontal and the vertical windings associated with the start of electron beam scanning of the cathode ray tube is connected to a potential reference level while the other extremities of the horizontal and vertical windings are connected to a source of deflection signals whereby undesired distortions appearing on the trace lines of the viewing screen are minimized.

United States Patent Torsch [4 1 June 20, 1972 54] DEFLECTION SYSTEM FOR TRIAD- FOREIGN PATENTS OR APPLICATIONS BEAM CATHODE RAY TUBE 514,170 11/1939 Great Britain ..335/210 [72] Inventor: Charles Edward Torsch, Rochester, Primary Examiner George Harris 73 Assign; s h m-i Mum 1 Attorney-Norman J. OMalley, Donald R. Castle and William H. McNeill [22] Filed: May 21, 1971 [21] Appl. No.: 145,884

Archer ..335/210 [57] ABSTRACT A cathode ray tube deflection system includes a triad-type cathode ray tube and a toroid-type deflection yoke having horizontal and vertical axes with first and second horizontal windings symmetrical to the horizontal axis in mirror image of one another about the vertical axis and first and second vertical winding symmetrical to the vertical axis in mirror image of one another about the horizontal axis and said first and second horizontal and vertical windings each including a flux altering means for enhancing vertical convergence of horizontal trace lines. The deflection yoke is formed by a process wherein a core of magnetic material is wrapped with wire turns applied in toroidal fashion to form first and second horizontal windings and first and second vertical windings advanced in opposite circumferential direction to form a mirror image relationship. Also, ringing is inhibited by circuitry wherein a specific terminal of each of the horizontal and the vertical windings associated with the start of electron beam scanning of the cathode ray tube is connected to a potential reference level while the other extremities of the horizontal and vertical windings are connected to a source of deflection signals whereby undesired distortions appearing on the trace lines of the viewing screen are minimized.

22 Claims, 13 Drawing Figures P'A'TENTEnJunzo I972 3. 671 .896

sum 10F 1 INVENTOR. CHARLES E. TORSCH 2.60.12 ATTORNEY PATENTEDJUiZO m2 $671,896

' sum 2 or '1 INVENTOR. CHARLES E. TORSCH ATTORNEY PATENTEDJUNZO 19. 2 3,671,896

SHEET 3 [IF 7 INVENTOR. CHARLES E. TORSCH PATENTEmunzo I972 3, 671 96 SHEET 0F 7 RIGHT HORIZONTAL LEFT-T HORIZONTAL TOP VERTICAL BOTTOM VERTICAL c Q i i- INVENTOR. CHARLES E. TORSCH ATTORNEY RIGHT SIDE HORIZONTAL COI L w- GROUP INTERCEPT O N p O) LEFT SIDE HORIZONTAL COIL W-GROUP INTERCEPT PAIENTEflJunzo me SHEET 5 [IF 7 0 l 0 50 DEGREES FROM HORIZ 6O 7O ONTAL AXIS so 90 I IO 20 3O DEGREES FROM HORIZONTAL AXIS 90 I INII-ZNTOR. CHARLES E.TORSCH ATTORNEY VERTICAL COIL W-GROUP INTERCE PT PATENTEDJUNZO 1912 3, 671 ,898

sum ear 7 l4 y/aa/ 0 IO 4O 5O 7O DEGREES FROM VERTICAL AXIS INVENTOR. CHARLES E. TORSCH JA Q. m

ATTORNEY DEFLECTION SYSTEM FOR TRIAD-BEAM CATI-IODE RAY TUBE CROSS-REFERENCE TO RELATED APPLICATION This application is a Streamlined Continuation of U.S. application Ser. No. 841,893 (now abandoned) filed July 15, 1969 in the name of Charles Edward Torsch.

BACKGROUND OF THE INVENTION Cathode ray tube deflection systems normally include a cathode ray tube and an associated deflection yoke. The cathode ray tube has a viewing screen which is impinged by one or more electron beams to provide a so-called scan raster and the deflectionyoke creates a magnetic field of altering strength and polarity which causes the electron beam to scan the viewing screento effect the scan raster.

In present day television receivers and especially in receivers employing a cathode ray tube wherein the electron guns and phosphors of the viewing screen are of a triad arrangement, the most common type of deflection yoke is the so-called "saddle" yoke. In the saddle" yoke construction, a pair of horizontal deflection windings are mounted on the top and bottom respectively of the cathode ray tube to produce a magnetic field parallel to a vertical axis. Also, a pair of vertical deflection windings are mounted on opposite sides of the cathode ray tube to effect a magnetic field parallel to a horizontal axis.

Although such devices have been and still are widely employed in triad-type cathode ray tube deflection systems, it has been found that such deflection yokes do leave something to be desired. More specifically, it has been found that saddletype deflection yokes provide electron beam deflection which is lacking in uniformity and consistency. Also, such deflection yokes employ a relatively large amount of expensive copper and ferrite materials, are relatively cumbersome and bulky, and are most difficult, if not impossible, to fabricate with uniformity.

Further, cathode ray tube deflection systems employing the above-mentioned "saddle" type deflection yokes also include aconvergence system whereby a plurality of electron beams emanating from a triad gun arrangement are converged to provide a scan raster on a viewing screen of the cathode ray tube. Moreover, well'known pin cushion correction circuitry employed in all known triad-type deflection systems is utilized to effect a substantially straight-sided raster.

Although the above-mentioned triad-type deflection systems employing a saddle" yoke do leave something to be desired, the only known attempt to overcome the above-mentioned problems is the provision of a so-called in-line deflection system. Therein, a cathode ray tube having a plurality of electron guns arrayed in a single plane is employed with a socalled toroid" type deflection yoke.

As set forth in US. Pat. No. 2,925,542 issued to R. B. Gethmann on Feb. 16, I960 and US Pat. No. 3,430,099 issued to R. B. Ashley on Feb. 25, I969, an in-line gun type of cathode ray tube evolves special problems which require a specific form of deflection yoke as well as a special form of convergence apparatus. As set forth therein, the deflection yoke apparatus provides a substantially straight-sided scan raster unsuitable to the normally employed convergence and pin-cushion circuitry common to triad-gun deflection systems, but rather adapted to size correction apparatus foreign to triad-gun systems.

Additionally, present day NT SC (National Television Systems Committee) color television receivers employ horizontal scanning by the electron beam at a rate of about 15,734 cycles per second with the electron beam scanning from left to right of the viewing screen, as seen by an observer, and rapidly re-tracing or returning to repeat the scan cycle. Also, the electron beam is advanced in a vertical direction from the top to the bottom of the cathode ray tube at a rate of about 60 cycles per second and rapidly returned to repeat the cycle.

As is well known, the abrupt change in value of a potential applied to the deflection windings to effect the rapid retrace of the electron beam and initiation of a following scan line causes the development of oscillations or spurious ringing" in the windings of the yoke. This undesired ringing" usually continues after the scanning period of the electron beam is started and appears as an undesired intensity variation or distortion at the left-hand portion of the viewing screen raster as observed by a viewer.

In order to minimize this undesired distortion due to ringing", it has been a common practice to employ circuitry such as set forth in US. Pat. No. 2,869,030 issued to M. Deranian et al. on Jan. 13, I959. Therein, a pair of horizontal deflection windings of the so-called saddle type are series connected, a pair of series connected capacitors of substan' tially equal value are shunted across the series connected windings, a resistor couples the junction of the series connected capacitors to the junction of the series connected deflection windings, one of the windings is coupled to a deflection signal source and the other winding to an AC potential reference level, and a capacitor is shunt connected across the winding coupled to the deflection signal source. Moreover, vertical saddle" windings are usually shunted by resistors to damp the capacitively coupled charge flow from the horizontal coils during and after horizontal retrace".

Obviously, the above-mentioned circuitry is complex as well as expensive incomponents and assembly time and skill. Moreover, the circuit complexity reduces reliability while adding undesired bulk and cost.

OBJECTS AND SUMMARY OF THE INVENTION It is an object of the present invention to provide an enhanced cathode ray tube deflection system. Another object of the invention is to provide an improved deflection yoke applicable to a television receiver deflection system. Still another object of the invention is to provide an enhanced process for fabricating improved deflection yokes for cathode ray tube deflection systems. A further object of the invention is to provide an improved deflection circuit arrangement for a television receiver. A still further object of the invention is to provide an improved process for fabricating an improved deflection yoke for use in an improved deflection circuitry arrangement. Still another object of the invention is to provide a toroidally wound deflection yoke and a deflection circuit arrangement suitable for replacement of thewell-known saddle yoke and deflection circuit arrangement employed in triad-gun type cathode ray tube systems.

These and other objects, advantages and capabilities are achieved in one aspect of the invention by a deflection yoke having a substantially circular core of magnetic material with first and second horizontal deflection windings toroidally wound thereon in mirror image of one another and oppositely disposed about a vertical axis. The deflection yoke is fabricated by a process wherein a circular core is selected and wrapped with toroidal wire turns to provide bank-wound wire groups which are intermittently spaced along the circumference of the core to provide a winding. Also, a deflection circuit arrangement for minimizing ringing currents in a deflection yoke includes a circuit means coupling one of a pair of series connected deflection windings associated with the start of electron beam scanning to a potential reference level and the other deflection winding to a deflection signal source.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional elevation of a cathode ray tube and associated toroidal deflection yoke;

FIG. 2 is a screen-end view diagram of the winding distribution of the exterior wires of a toroidal yoke embodiment of the invention;

FIG. 2A illustrates flux altering means in the form of shortcircuited turns of FIG. 2;

FIG. 3 is a planar view illustrating the form of a pair of horizontal windings;

FIG. 4 is an elevation view illustrating the form of a pair of vertical windings;

FIGS. 5, 6 and 7 illustrate a cathode ray tube raster as observed by a viewer;

FIGS. 8 and 9 are graphical representations of the horizontal deflection windings;

FIG. 10 is a graphical representation of a vertical deflection winding;

FIG. 11 is an illustration, in block and schematic form, of a television receiver and associated deflection circuit arrangement for a cathode ray tube; and

FIG. 12 is a schematic illustration of the winding of a toroidal deflection yoke and associated deflection circuit arrangement.

DESCRIPTION OF THE PREFERRED EMBODIMENT For a better understanding of the present invention, together with other and further objects, advantages and capabilities thereof, reference is made to the following disclosure and appended claims in conjunction with the accompanying drawings.

Referring to the drawings, FIG. 1 illustrates a typical cathode ray tube deflection system including a triad type cathode ray tube 5, a deflection yoke 7, and a convergence coil 9. The cathode ray tube 5 includes a viewing screen 11 which is impinged by one or more electron beams 13 derived from one or more electron guns 15.

In cathode ray tube systems wherein the cathode ray tube 5 includes a plurality of electron beams 13 derived from a plurality of electron guns 15, a convergence coil 9 is normally disposed rearwardly, as viewed by a cathode ray tube observer, of the viewing screen 11 and of the deflection yoke 7. This convergence coil 9 serves to effect convergence of the plurality of electron beams 13 at or near the surface of the viewing screen 11 of the cathode ray tube 5.

Also, the deflection yoke 7 is affixed to the cathode ray tube 5 and located rearwardly of the viewing screen 11. This deflection yoke 7 is generally operable in a manner wellknown in the art to effect deflection of the electron beams 13 in both horizontal and vertical directions. Moreover, the deflection yoke 7, as employed in all known present day television receivers, causes electron beam scanning which progresses from left to right and top to bottom of the viewing screen 11.

Further, the deflection yoke 7 is of the toroidal type having a substantially circular core 16 of a magnetic material having a relatively high permeability factor, 100 or more for instance, and a plurality of windings of wire turns 17 wrapped in toroidal fashion on the circular core 16. As to the wire turns 17 and toroidal windings, reference is made to the schematic illustration of FIG. 2.

In FIG. 2, a preferred wire configuration form includes a substantially circular core 16 of magnetic material supporting a plurality of toroidal wrapped wire turns. For clarity, only those turns in abutting relationship to the outer surface of the core 16 are illustrated. Also, a preferred wire configuration form includes at least one of such features as interlaced deflection windings, sawtooth"-wound deflection windings, mirror-image deflection windings, intermittent bank-wound deflection windings, deflection windings having a flux altering means, intermittent bank-wound deflection windings having added turns, and deflection windings affixed by a process which includes advancement in opposite circumferential directions. Moreover, the above-mentioned features will be explained hereinafter.

More specifically, the wire configuration of FIG. 2 includes a horizontal axis I-I-I-I' and a vertical axis designated V-V'. A first or left horizontal deflection winding 19, represented by blackened dots, is disposed to the left of the vertical axis V-V' and a second or right horizontal deflection winding 21, represented by blackened dots, is disposed to the right of the vertical axis V-V'. Moreover, the wire configuration and windings 19 and 21 of FIG. 2 are illustrated in the same positional location as they would appear to a viewer of the display screen 11 of the cathode ray tube 5 of FIG. 1, with the deflection yoke 7 attached thereto.

As can be seen, each of the horizontal deflection windings 19 and 21 is substantially symmetrical with respect to the horizontal axis H-H'. Moreover, each of the horizontal deflection windings 19 and 21 includes a flux altering means 23 and 25 respectively, centrally disposed about the horizontal axis I-I-I-I' which, in this instance, is illustrated as a winding gap. Obviously, short-circuited turns, shielded turns, and similar techniques for altering a flux pattern would be equally appropriate as illustrated by the turns 24, 26, 36, and 38 shortcircuited by a metal member 28.

Also, each of the horizontal deflection windings l9 and 21 includes a plurality of wire groups or groups of wire turns in intermittent circumferential spaced relationship about the circular core 16. Each of these groups of wire turns has a centrally located force of magnetic influence and is preferably in the form of an intermittent bank winding wherein a first layer of turns includes at least one pair of adjacent turns and a second layer of turns includes a wire turn contacting and supported by the pair of adjacent turns of the first layer of turns. Should the wire group include more than a single pair of adjacent turns in the first layer of turns, the second layer of turns would include a wire turn contacting and supported by each pair of turns of the first layer.

These particular intermittent bank-wound horizontal deflection windings l9 and 21 each include added turns 27/28 and 29/30 respectively, disposed on opposite sides of the flux altering means 23 and 25. Moreover, these added turns 27/28 and 29/30 are preferably disposed in substantially similar but not necessarily identical circumferential spaced relationship to the flux altering means 23 and 25, and serve to enhance electron beam convergence, as will be explained hereinafter.

Further, the first and second horizontal deflection windings l9 and 21 are preferably, not necessarily, in complete mirrorimage relationship to one another about the vertical axis V-V'. As can readily be seen in the illustrative example of FIG. 3, the first horizontal deflection winding 19 and the second horizontal deflection winding 21 are affixed in reversed progression to effect the above-described mirrorimage relationship about the vertical axis V-V, as observed on the exterior surface of the core member 16.

Additionally, the above-mentioned mirror-image relationship between the first and second deflection windings is preferably, not necessarily, an identical relationship. In this specific illustration, referring back to FIG. 2, the circumferential spacing of the added turns 27 and 28 of the first deflection winding 19 with respect to the horizontal axis I-I-I-I differs from the circumferential spacing of the added turns 29 and 30 of the second deflection winding 21. Thus, the abovedescribed mirror-image relationship is effected except for this slight deviation of the added turns 27 and 28 and 29 and 30.

Interleaved with the first and second horizontal deflection windings 19 and 21 and symmetrically disposed about the vertical axis V-V' is a first or top vertical deflection winding 31 and a bottom or second vertical deflection winding 33, both represented by white circles in the illustration of FlG.2. Each of these vertical deflection windings 31 and 33 is symmetrical to the vertical axis V-V and disposed in mirror image relationship about the horizontal axis I-I-I-I. Also, each vertical deflection winding 31 and 33 includes a flux altering means 35 and 37 which is also symmetrically disposed about the vertical axis V-V.

As was previously explained with respect to the horizontal deflection windings 19 and 21, each of the vertical deflection windings 31 and 33 is in the form of intermittent circumferentially spaced wire groups. However, the vertical deflection windings 31 and 33 are in the form of intermittent spaced wire groups which are electrically connected in a sawtooth manner. Therein, the first layer of turns of the total winding are serially connected and advanced in one circumferential direction. The second layer of turns is applied to the first layer and advanced in the same circumferential direction. As a result, the potential difference between adjacent turns of the first and second layers is more nearly constant.

Also, as can be readily seen in the illustrative example of FIG. 4, the first vertical deflection winding 31 and the second vertical deflection winding 33 are affixed to the core member 16 in reversed progression. In this manner, the first and second vertical deflection windings 31 and 33 provide a mirror-image relationship with respect to one another about a horizontal axis l-l-H as observed from the exterior surface of the core member 16, from either left or right side of the yoke.

Thus, there has been provided a toroid deflection yoke having interleaved first and second horizontal and first and second vertical deflection windings, l9 and 21 and 31 and 33. The horizontal deflection windings 19 and 21 are each in vertical symmetrical relationship about the horizontal axis 11-1-1 and in substantial mirror-image relationship to one another about the vertical axis V-V. Also, each of the horizontal deflection windings l9 and 21 is in bank-wound form and respectively includes a flux altering means 23 and 25 and added turns 27/28 and 29/30 symmetrically disposed about the horizontal axis l-l-H.

Similarly, the vertical deflection windings 31 and 33 are horizontally symmetrical about the vertical axis V-V' and in mirror-image of one another about the horizontal axis l-l-l-l'. Moreover, the vertical deflection windings 31 and 33 are of sawtooth-connected form and respectively include a flux altering means 35 and 37.

As to the fabrication of a toroid type deflection yoke, a substantially circular core 16 of magnetic material having a horizontal and a vertical axis is selected. Wire turns are wrapped in toroidal fashion on opposite sides of the horizontal axis l-l-H' of the core 16 and advanced in opposite circumferential directions to provide first and second vertical deflection windings 31 and 33. Also, wire turns are wrapped in toroidal fashion on opposite sides of the vertical axis V-V' of the core 16 and advanced in opposite circumferential directions to provide first and second horizontal deflection windings 19 and 21. Moreover, the windings are circumferentially spaced such that interleaving of the vertical and horizontal windings is effected.

More specifically, a preferred process for fabricating a toroid-type deflection yoke of the type illustrated in FIG. 2 includes selecting a substantially circular core 16 of a magnetic material. Then, the first layer of turns of the vertical deflection windings 31 and 33 are wrapped in toroidal fashion about the circular core 16; This first layer of turns includes intermittent circumferentially spaced pairs of wire turns which are advanced in opposite circumferential directions on the core 16 and disposed on opposite sides of the horizontal axis of the core 16. Thus, the first layer of turns of both the first and second vertical deflection windings 31 and 33 define intermittent circumferential spaces along the core 16.

Following, the first and second horizontal deflection windings 19 and 21 are applied to the core 16 in interleaved relationship with the first and second vertical deflection windings 31 and 33. The first and second horizontal deflection windings 19 and 21 are formed by wrapping wire turns in toroidal fashion about the core 16 and aflixing these toroidal wrapped wire turns to the core 16 in the intermittent circumferential spaces defined by the first layer of wire turns of the first and second vertical deflection windings 31 and 33. Moreover, the first and second horizontal deflection windings 19 and 21 are oppositely disposed with respect to the vertical axis V-V' and are advanced in opposite circumferential directions.

In the actual application of one of the horizontal deflection windings 19 and 21, at least one pair of toroidal wrapped wire turns is affixed to the core 16 within a space defined by the vertical deflection windings 31 and 33. Then, a toroidal wrapped turn of a second layer contacts and is supported by the pair of wire turns of the first layer to provide a wire group. Also, the wire turns of the first and second layers are serially connected to minimize the potential difference therebetween which, in turn, minimizes insulation requirements.

Further, the winding then advances to the following space defined by the first layer of the vertical deflection windings 31 and 33. Moreover, a plurality of pairs of turns may be affixed to the core 16 with the second layer of turns including a first turn supported by the first pair of turns of the first layer and following turns advancing in the same circumferential direction as the first layer of turns with a second layer turn contacting and supported by each advancing pair of turns of the first layer.

Thus, each of the horizontal deflection windings l9 and 21 is of the so-called bank-wound form wherein each turn of a second layer of turns is supported by a pair of turns of a first layer of turns. Also, the turns of the first and second layers of turns are advanced in the same circumferential direction. Moreover, the wire turns of the vertical deflection windings 31 and 33 serve to confine the wire groups of the horizontal deflection windings 19 and 21 to a restricted space preventing undesired distortion and spreading of the first layer of turns by the force exerted thereon by the second layer of turns.

Following, a second layer of toroidal wrapped wire turns is applied to the vertical deflection windings 31 and 33. This second layer of turns starts in the same location and advances in the same direction as the first layer of turns of each of the vertical deflection windings 31 and 33. Also, the final turn of the first layer of turns of each of the vertical deflection windings 31 and 33 is connected electrically to the first turn of the second layer of turns. This type connection is normally referred to as a sawtooth connection whereby the potential difference intermediate adjacent turns of the first and second layers is substantially constant throughout the total winding.

Thus, the first and second vertical deflection windings 31 and 33 are affixed to the core 16 by applying a first layer of spaced turns advanced in opposite circumferential direction. The first and second horizontal deflection windings 19 and 21 are interleaved with the vertical deflection windings 31 and 33 within the spaces provided by the first layer thereof. These horizontal deflection windings 19 and 21 are of a bank-wound form with first and second layers of wire turns forming wire groups and the wire turns and wire groups serially connected. Then, the second layer of turns of the vertical deflection windings 31 and 33 are applied to the first layer to fonn wire groups advancing in opposite circumferential directions and electrically connected in a sawtooth connection.

As to operation of a toroidal-wound deflection yoke 7 in conjunction with a triad-type cathode ray tube 5, it may first be assumed that the flux altering means 23 and 25 of the first and second horizontal deflection windings l9 and 21 are omitted, as well as the flux altering means 35 and 37 of the first and second vertical deflection windings 31 and 33. Also, it is assumed that the added turn pairs 27/28 and 29/30 have not been included in the first and second horizontal deflection windings 19 and 21.

Under these conditions, it was found thatthe observer of the viewing screen 11 of a triad-gun type color cathode ray tube 5 tended to see a substantially straight-sided raster, illustrated in FIG. 5. However, the raster has what is commonly referred to as a reverse red trapazoid wherein the red and green traces have opposing slopes with the separation of the green traces at a minimum to the right of the viewing screen 11 as observed by a viewer. Moreover, it was found that convergence of the traces of a color receiver wherein the abovementioned reverse red trapazoid is present was most difficult, if not impossible, with convergence circuitry normally available in present-day television receivers utilizing triadgun type cathode ray tubes.

Further, it was found that the inclusion of the flux altering means 23 and 25 in the horizontal deflection windings 19 and 21 and centered about the horizontal axis l-l-H' tended to cause what is classically described as a barrel" effect or overcorrection of the magnetic flux within the toroid deflection yoke 7 of FIG. 1. This barrel effect of the magnetic flux appears as a so-called pin-cushioned" raster (see FIG. 6) as seen by a viewer of the screen 11 of a color cathode ray tube 5. Moreover, such over-correction of the magnetic flux field tended to provide what is known as a forward red trapazoid" wherein the red and green traces have opposing slopes with the separation of the red traces at a minimum to the right of the viewing screen 11. Again, convergence with available apparatus was difficult, if not impossible.

However, it was found that the above-mentioned reverse red trapazoid effect, due to under-correction of the magnetic flux field and the forward red trapazoid effect due to overcorrection of the magnetic flux field, could be virtually eliminated by the proper selection of flux corrective measures. Thus, the employment of the flux altering means 23 and 25 in conjunction with the pairs of added turns 27, 28 and 29,30 properly spaced therefrom, provide a raster with red and green traces having substantially coincident arcs as illustrated in FIG. 7. Having rendered the slopes of the red and green arcs substantially coincident, it was found that the pin-cushioned raster is readily correctable by pin-cushion and convergence circuitry already available in most present day color television receivers.

Thus, the pin-cushion circuitry readily available in triad-gun type color television receivers is employed, in the usual manner, to effect pin-cushion correction and convergence of the red and green traces of the electron beams of a color cathode ray tube. Therefore, the toroid deflection yoke 7 is employable with a television receiver having the usual triadgun type cathode ray tube, pin-cushion correction circuitry and convergence apparatus to provide a desired color image display.

It should perhaps be further noted that the specific embodiment of a toroid-wound deflection yoke illustrated in FIG. 2 includes the added turns 27 and 28 of the first or left horizontal deflection winding 19, as well as the added turns 29 and 30 of the second or right horizontal deflection winding 21. Also, the added turns 27 and 28 are at a slightly different circumferential spacing from the horizontal axis H-H than the added turns 29 and 30 due to the effect of the earth s magnetic field in the Northern Hemisphere.

More specifically, FIGS. 8 and 9 will serve to illustrate the winding distribution of the horizontal deflection windings 19 and 21 in a quadrant to the lefi and right of the vertical axis V-V. Therein, the x-axis represents the angular degrees 6 from the horizontal axis I-IH' while the y-axis numerals W represent the rim-order intercept of a wire group with respect to the horizontal axis H-H'. Each of the wire groups W is considered to be a unit, three toroid turns in this instance, having a central acting vector unit of force insofar as the magnetic effect and angular degrees are concerned. Moreover, the wire and turn content of each of the wire groups W is varied to provide variations in impedance and may include one or a number of turns depending upon the impedance value desired.

Referring to FIG. 8, the curve is representative of the upper left quadrant as well as the lower left quadrant of the first or left horizontal deflection winding 19 since the winding is substantially symmetrical with respect to the horizontal axis H-H'. This curve of FIG. 8 may be represented by the following formulation:

0.0000682560 0000000384020 wherein 6 degrees from the horizontal axis H-H' to the center of influence of a wire group W W! rim-order intercept of a wire group W in the left horizontal deflection winding 19 The upper right quadrant of the second or right horizontal deflection winding 21 is illustrated by the diagram of FIG. 9. As mentioned above, the lower right quadrant of the horizontal deflection winding 21 is also represented by the diagram of FIG. 9. In a formulation of the curve:

Wr= 0.05 101 0.43525 00.0062l0 0.000076430 0.00000042966 wherein 0 degrees from the horizontal axis H-H' to the center of influence of a wire group W Wr rim-order intercept of a wire group W in the right horizontal deflection winding 21.

Additionally, FIG. 10 will serve to illustrate the winding distribution of the vertical deflection windings 31 and 33. Herein, the x-axis represents the angular degrees 45 from the vertical axis V-V' while the y-axis numerals represent the rim-order intercept of a wire group W with respect to the vertical axis V-V'. As mentioned above, each of the wire groups W represent a central acting vector of force, three toroid turns in this instance, of the vertical windings 31 and 33. FIG. 10 will serve to represent quadrants to the left and right of the vertical axis V-V', as well as above and below the horizontal axis H-H, since the windings are symmetrical.

As represented by formulation:

Wv 0.11898 0.346731.10.00l864ml: d: degrees from the vertical axis V-V to the center of influence of a wire group W Wv rim-order intercept of a wire group W in the first and second vertical deflection windings 31 and 33.

It should be noted that toroid-wound deflection yokes have been fabricated wherein both the first and second horizontal deflection windings l9 and 21 and the first and second vertical deflection windings 31 and 33 are symmetrical. In this instance, it has been found that the formulation Wr representative of the right horizontal deflection winding 21 is also employed in fabricating the left horizontal deflection winding 19. Moreover, it has been found that satisfactory results have been obtained when the degrees 0 from the horizontal axis H-H and the degrees 41 from the vertical axis V-V' to the center of influence of the wire group W are not varied from the above formulations by more than about three degrees (3).

As to the employment of the above-described toroidal deflection yoke, FIG. 11 illustrates a typical television receiver employing the usual antenna 38 whereat transmitted television signals are intercepted and applied to a signal receiver 39. The signal receiver 39 includes the usual RF and IF signal amplifier and detector stages and provides an output signal which is applied via an audio amplifier stage 40 to a loudspeaker 41. Another output from the signal receiver 39 includes signals representative of both luminance and synchronizing information and is applied to a video amplifier stage 43.

One output signal available from the video amplifier stage 43 and representative of luminescence information is applied to a control electrode of a cathode ray tube 45. Another output signal available from the video amplifier stage 43 and representative of synchronizing information is applied to a synchronizing separator stage 47. Therein, signals representative of vertical and horizontal scan frequencies are derived and applied to vertical and horizontal deflection stages 49 and 51 respectively.

The vertical deflection stage 49 is coupled via an output transformer 53 to a pair of output terminals Y-Y' and one of the output terminals Y is AC coupled by a capacitor 54 to a potential reference level such as circuit ground. In turn, the output terminals Y-Y' are coupled to a pair of series connected vertical deflection coil windings, 55 and 57 associated with a cathode ray tube 45.

In a somewhat similar manner, the horizontal deflection stage 51 is coupled to a horizontal output transformer winding 59. One end of the transformer winding 59 is coupled by way of a rectifier stage 61 to a high voltage electrode of the cathode ray tube 45 while the other end of the transformer winding 59 is coupled via a capacitor 68 to a DC potential source 8+. Also, a series connected damper stage 65 and alterable inductor 67, linearity control, shunted by a tuning capacitor are coupled intermediate a junction of the transformer winding 59 and the DC potential source B+.

Further, a pair of series connected horizontal deflection coils 69 and 71 associated with the cathode ray tube 45 have one end thereof connected to a junction 73 of the transformer winding 59 and the other end coupled via the capacitor 63 to the DC potential source 13+ and to the transformer winding 59. Moreover, a capacitor 75 is shunted across the horizontal deflection coil 71 connected to the end of the transformer winding 59 via capacitors 63 and 68 and to the potential source 3+.

As can be more readily seen in FIG. 12, a toroidal-wound deflection yoke is schematically illustrated in cooperation with a triad-type color cathode ray tube. Herein, the neck portion 77 of a color cathode ray tube includes the triad of electron guns 79 and is surrounded by the toroid-wound deflection yoke 81.

As observed by a viewer of the screen of a cathode ray tube, the first or left horizontal deflection winding 71 is associated with the beginning of the usual left to right horizontal scanning of the cathode ray tube. This winding 71 is AC coupled by a capacitor 63 to a DC potential source B+. A capacitor 75 shunts the winding 71 and a second or right horizontal deflection winding 69 series connects the first horizontal deflection winding 71 to a horizontal deflection signal source, 73 of FIG. 11. Moreover, a portion of the transformer winding 59 is coupled by the storage boost capacitor 68 to the DC potential source B+.

In a somewhat similar manner, a first or top vertical deflection winding 57 associated with the beginning of vertical scanning is AC coupled by a capacitor 54, to a potential reference level such as circuit ground. The first vertical deflection winding 57 is series connected to a second vertical deflection winding 55 coupled to a vertical deflection signal source Y" of FIG. 11.

As to the operation of theabove-described circuitry illustrated in FIGS. 11 and 12 in conjunction with the toroid deflection yoke 7, it is to be noted that the left or first horizontal deflection winding 71 and the first or top vertical deflection winding 57 are concerned with the start of both horizontal and vertical scanning. Also, the previously mentioned opposing circumferential directions of advancement of the windings serves to effect neutralization of the electrostatic charging of the distributed capacitance between first and second vertical deflection windings 57 and 55 and the first and second horizontal deflection windings 71 and 69.

Further, the mirror image relationship of the windings assists in neutralizing magnetic and electrostatic cross-induction between the horizontal windings 69 and 71 and the vertical windings 55 and 57. This neutralization of electrostatic and magnetic cross-induction between horizontal and vertical winding is also aided by the substantially sawtooth connection of the vertical windings 57 and 55 as well as the intermittent bank-wound type connections of the horizontal windings 71 and 69.

Additionally, the first horizontal deflection winding 71 most closely associated with the ringing effect has one end thereof coupled via the capacitor 63 to a potential reference level 8+ with the other end closely associated with the grounded end of the vertical deflection winding 57. Moreover, the horizontal winding 71 and the vertical winding are interleaved which also assists in draining undesired energy from both the horizontal and vertical windings 71 and 57 associated with the start of both horizontal and vertical scan.

Moreover, undesired energy drain of the horizontal deflection winding 71 is even further enhanced by the shunting capacitor 75. Again, the shunting capacitor 75 provides a rapid path for energy drain to the potential reference level 3+.

Thus, it has been found that a viewer is subjected to a minimum of ringing" by employment of a circuit arrangement wherein the deflection winding associated with the beginning of electron beam scanning is coupled to a reference level while the winding associated with the end of electron beam scanning is coupled to the signal source. Moreover, the arrangement is inexpensive of parts and of enhanced reliability as a result of the relative simplicityv of the structure.

' While there has been shown and described what is at present considered the preferred embodiments of the present invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention as defined by the appended claims.

lclaim: l. A color cathode ray tube system comprising: a triad-type color cathode ray tube having a viewing screen; and a toroidwound deflection yoke associated with said tube and includ- I mg: a

a substantially circular core of magnetic material having a horizontal axis and a vertical axis; first and second horizontal deflection windings toroidally wrapped about said core on opposite sides of said vertical axis; first and second vertical deflection windings toroidally wrapped about said core on opposite sides of said horizontal axis; and

flux altering means in the form of a winding gap in each of said first and second horizontal deflection windings, said gaps of each of said windings being substantially centered about and symmetrical to said horizontal axis to effect a substantially symmetrical appearance of horizontal trace lines on said viewing screen from at least two electron guns of said triad-type cathode ray tube. 2. The system of claim 1 wherein said flux altering means is in the form of short-circuited turns in each of said first and second horizontal deflection windings with said short-circuitedturns of each of said windings being substantially centered about and symmetrical to said horizontal axis.

3. The system of claim 1 including turns added to each of said first and second horizontal deflection windings, said added turns being spaced from and substantially symmetrical to said horizontal axis.

4. The system of claim 1 wherein said first and second vertical deflection windings each include a flux altering means in the form of a winding gap substantially centered about and symmetrical to said vertical axis.

5. The system of claim 1 wherein said first and second vertical deflection windings each include a flux altering means in the form of short-circuited turns substantially centered about and symmetrical to said vertical axis.

6; The system of claim 1 wherein said flux altering means includes added turns substantially symmetrical to said horizontal axis and included in each of said first and second horizontal deflection windings.

7. The combination of claim 1 wherein said first and second horizontal deflection windings are substantially defined by a formula of the form:

Wr=-0.05101 0.43525 0 0.0062l6 0.000076430 wherein 0 degrees from the horizontal axis H-I-I' to the center of wire group W Wr= rim-order intercept of a wire group W of the horizon tal deflection windings wherein 0 is varied by not more than about 33 in the above formulation.

8. The system of claim 1 wherein said first and second vertical deflection windings are substantially defined by a formula of the form:

Wv 0.11898 0.34673 0.001864l (15 wherein 4; degrees from the vertical axis V-V' to the center of a wire group W; Wv a rim-order intercept of a wire group W of the vertical deflection windings; wherein 4a is varied by not more than about 3 in the above formulation.

9. The system of claim 1 wherein said first horizontal deflection winding is substantially defined by a formula of the form:

0.000068256 0 0.00000038402 0 said second horizontal deflection winding by a formula of the form:

Wr 0.05101 0.43525 0.00621 (.9 0.00007643 0 0.0000004296 6 wherein 6 degrees from the horizontal axis l-lH' to the center of a wire group W;

WI rim-order intercept of a wire group in the left horizon tal deflection winding;

Wr rim-order intercept of a wire group in the right horizontal deflection winding; wherein 0 is varied by not more than about 3 in the above formulation; differing in circumferential spacing from said added turns of said second winding.

10. In a color cathode ray tube deflection system employing a multi-gun triad type color cathode ray tube having a viewing screen, a deflection yoke comprising:

a substantially circular core of magnetic material having a horizontal axis and a vertical axis;

first and second vertical deflection windings toroidally wrapped about said core; and

first and second horizontal deflection windings toroidally wrapped about said core, each of said windings being centered about said horizontal axis, oppositely disposed about said vertical axis in substantially mirror-image relationship to one another and circumferentially spaced and interleaved with said first and second vertical deflection windings.

11. The combination of claim 10 wherein said first and second vertical deflection windings are oppositely disposed in mirror image relationship to one another about said horizontal axis of said core.

12. In a color cathode ray tube deflection system employing a triad-type color cathode ray tube deflection yoke comprising in combination:

a substantially circular core of magnetic material having a horizontal and a vertical axis;

first and second vertical deflection windings toroidally wrapped about said core, each of said windings being 0ppositely disposed about said horizontal axis in mirrorimage relationship to one another and including sawtooth-connected multiple wire layers; and

first and second horizontal deflection windings toroidally wrapped about said core and oppositely disposed in mirror-image relationship to one another about said vertical axis.

13. The combination of claim 12 wherein each of said first and second horizontal deflection windings is in the form of an intermittent bank winding having each single turn of a second layer of turns supported by a single pair of adjacent turns of a first layer of turns.

14. The combination of claim 12 wherein each of said first and second vertical deflection windings includes a flux altering means.

15. The combination of claim 12 wherein each of said first and second horizontal deflection windings includes a flux altering means.

16. The combination of claim 13 wherein each of said first and second horizontal deflection windings includes a fiux altering means in the form of a combination winding gap and added turns to the intermittent bank winding.

17. A color cathode ray tube system comprising:

a triad-type color cathode ray tube having a plurality of electron guns and a viewing screen; and

a toroidal deflection yoke associated with said cathode ray tube, said yoke including a substantially circular core of magnetic material having horizontal and vertical axes and first and second horizontal and vertical deflection windings toroidally wrapped about said core, said horizontal windings disposed upon opposite sides of said vertical axis and said vertical windings disposed upon opposite sides of said horizontal windings to provide the appearance on said viewing screen of at least two horizontal trace lines derived from at least two electron guns and having substantiall similar arcs. 18. The color catho e ray tube system of claim 17 wherein said substantially similar arcs of said two horizontal trace lines have substantially identical slopes.

19. The color cathode ray tube system of claim 17 wherein said two horizontal trace lines are red and green trace lines.

20. The color cathode ray tube system of claim 17 wherein said first and second horizontal deflection windings are in the form of intermittent bank windings having a first layer of turns including at least one pair of adjacent turns and a second layer of turns including at least one turn contracting and supported by said pair of turns of said first layer of turns.

21. The color cathode ray tube system of claim 17 wherein said first and second vertical deflection windings are in the form of sawtooth-connected multiple wire layers having a second layer of turns serially connected to a first layer of turns and advanced in the same circumferential direction.

22. The color cathode ray tube system of claim 17 wherein said first and second horizontal deflection windings are in the form of intermittent bank windings and said first and second vertical deflection windings are in the form of sawtooth-connected multiple wire layers advancing in the same circumferential direction. 

1. A color cathode ray tube system comprising: a triad-type color cathode ray tube having a viewing screen; and a toroidwound deflection yoke associated with said tube and including: a substantially circular core of magnetic material having a horizontal axis and a vertical axis; first and second horizontal deflection windings toroidally wrapped about said core on opposite sides of said vertical axis; first and second vertical deflection windings toroidally wrapped about said core on opposite sides of said horizontal axis; and flux altering means in the form of a winding gap in each of said first and second horizontal deflection windings, said gaps of each of said windings being substantially centered about and symmetrical to said horizontal axis to effect a substantially symmetrical appearance of horizontal trace lines on said viewing screen from at least two electron guns of said triadtype cathode ray tube.
 2. The system of claim 1 wherein said flux altering means is in the form of short-circuited turns in each of said first and second horizontal deflection windings with said short-circuited turns of each of said windings being substantially centered about and symmetrical to said horizontal axis.
 3. The system of claim 1 including turns added to each of said first and second horizontal deflection windings, said added turns being spaced from and substantially symmetrical to said horizontal axis.
 4. The system of claim 1 wherein said first and second vertical deflection windings each include a flux altering means in the form of a winding gap substantially centered about and symmetrical to said vertical axis.
 5. The system of claim 1 wherein said first and second vertical deflection windings each include a flux altering means in the form of short-circuited turns substantially centered about and symmetrical to said vertical axis.
 6. The system of claim 1 wherein said flux altering means includes added turns substantially symmetrical to said horizontal axis and included in each of said first and second horizontal deflection windings.
 7. The combination of claim 1 wherein said first and second horizontal deflection windings are substantially defined by a formula of the form: Wr -0.05101 + 0.43525 theta -0.00621 theta 2 + 0.00007643 theta 3 wherein theta degrees from the horizontal axis H-H'' to the center of a wire group W Wr rim-order intercept of a wire group W of the horizontal deflection windings wherein theta is varied by not more than about 3* in the above formulation.
 8. The system of claim 1 wherein said first and second vertical deflection windings are substantially defined by a formula of the form: Wv 0.11898 + 0.34673 phi -0.0018641 phi 2; wherein phi degrees from the vertical axis V-V'' to the center of a wire group W; Wv a rim-order intercept of a wire group W of the vertical deflection windings; wherein phi is varied by not more than about 3* in the above formulation.
 9. The system of claim 1 wherein said first horizontal deflection winding is substantially defined by a formula of the form: Wl -0.07469 + 0.428558 theta -0.0057716 theta 2 + 0.000068256 theta 3 -0.00000038402 theta 4 said second horizontal deflection winding by a formula of the form: Wr 0.05101 + 0.43525 theta -0.00621 theta 2 + 0.00007643 theta 3 -0.0000004296 theta 4 wherein theta degrees from the horizontal axis H-H'' to the center of a wire group W; Wl rim-order intercept of a wire group in the left horizontal deflection winding; Wr rim-order intercept of a wire group in the right horizontal deflection winding; wherein theta is varied by not more than about 3* in the above formulation; differing in circumferential spacing from said added turns of said second winding.
 10. In a color cathode ray tube deflection system employing a multi-gun triad type color cathode ray tube having a viewing screen, a deflection yoke comprising: a substantially circular core of magnetic material having a horizontal axis and a vertical axis; first and second vertical deflection windings toroidally wrapped about said core; and first and second horizontal deflection windings toroidally wrapped about said core, each of said windings being centered about said horizontal axis, oppositely disposed about said vertical axis in substantially mirror-image relationship to one another and circumferentially spaced and interleaved with said first and second vertical deflection windings.
 11. The combination of claim 10 wherein said first and second vertical deflection windings are oppositely disposed in mirror image relationship to one another about said horizontal axis of said core.
 12. In a color cathode ray tube deflection system employing a triad-type color cathode ray tube deflection yoke comprising in combination: a substantially circular core of magnetic material having a horizontal and a vertical axis; first and second vertical deflection windings toroidally wrapped about said core, each of said windings being oppositely disposed about said horizontal axis in mirror-image relationship to one another and including sawtooth-connected multiple wire layers; and first and second horizontal deflection windings toroidally wrapped about said core and oppositely disposed in mirror-image relationship to one another about said vertical axis.
 13. The combination of claim 12 wherein each of said first and second horizontal deflection windings is in the form of an intermittent bank winding having each single turn of a second layer of turns supported by a single pair of adjacent turns of a first layer of turns.
 14. The combination of claim 12 wherein each of said first and second vertical deflection windings includes a flux altering means.
 15. The combination of claim 12 wherein each of said first and second horizontal deflection windings includes a flux altering means.
 16. The combination of claim 13 wherein each of said first and second horizontal deflection windings includes a flux altering means in the form of a combination winding gap and added turns to the intermittent bank winding.
 17. A color cathode ray tube system comprising: a triad-type color cathode ray tube having a plurality of electron guns and a viewing screen; and a toroidal deflection yoke associated with said cathode ray tube, said yoke including a substantially circular core of magnetic material having horizontal and vertical axes and first and second horizontal and vertical deflection windings toroidally wrapped about said core, said horizontal windings disposed upon opposite sides of said vertical axis and said vertical windings disposed upon opposite sides of said horizontal windings to provide the appearance on said viewing screen of at least two horizontal trace lines derived from at least two electron guns and having substantially similar arcs.
 18. The color cathode ray tube system of claim 17 wherein said substantially similar arcs of said two horizontal trace lines have substantially identical slopes.
 19. The color cathode ray tube system of claim 17 wherein said two horizontal trace lines are red and green trace lines.
 20. The color cathode ray tube system of claim 17 wherein said first and seCond horizontal deflection windings are in the form of intermittent bank windings having a first layer of turns including at least one pair of adjacent turns and a second layer of turns including at least one turn contracting and supported by said pair of turns of said first layer of turns.
 21. The color cathode ray tube system of claim 17 wherein said first and second vertical deflection windings are in the form of sawtooth-connected multiple wire layers having a second layer of turns serially connected to a first layer of turns and advanced in the same circumferential direction.
 22. The color cathode ray tube system of claim 17 wherein said first and second horizontal deflection windings are in the form of intermittent bank windings and said first and second vertical deflection windings are in the form of sawtooth-connected multiple wire layers advancing in the same circumferential direction. 